Definition: You are given a question on computer security. You are also given 4 answer options (associated with "A", "B", "C", "D"), out of which only one is correct. You need to answer the question by selecting the correct option. You should only answer with the choice letter, not the whole answer.
Input: Exploitation of the Heartbleed bug permits
(A)overwriting cryptographic keys in memory (B)a kind of code injection (C)a read outside bounds of a buffer (D)a format string attack

C